The present invention pertains to sprinklers such as are employed for fire extinguishing purposes, and more particularly pertains to sprinklers that are flush mounted in the ceiling or a sidewall of a structure being protected against fire.
Despite their indisputed effectiveness in fighting fires, automatic or manually operated sprinkler systems are sometimes regarded to be esthetically distasteful when the sprinkler heads are visible after the system is installed. In an effort to overcome this problem, various types of flush mounted sprinklers have been proposed, e.g. as disclosed in U.S. Pat. Nos. 2,389,331; 2,558,450; 3,198,258; 3,459,266 and 3,714,989. Problems with prior flush mounted sprinklers have been largely associated with the fact that the deflector for producing a spray or droplets must be retained in a retracted position inside a recessed receptacle prior to a fire, and must somehow be moved to a position outside the receptacle when a fire occurs, otherwise the ceiling or wall in which the sprinkler is mounted can seriously interfere with the intended liquid distribution pattern of the sprinkler when it is spraying water. Previous apparatus combinations for effecting concealment of the sprinkler while also providing for extension of the deflector to an operating position during a fire have frequently been too complex and costly, or of doubtful reliability.